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Gamow-Teller Transitions for Light Nuclei by the Deformed Quasi-particle RPA(DQRPA)

Gamow-Teller Transitions for Light Nuclei by the Deformed Quasi-particle RPA(DQRPA). Soongsil University, Korea Eun Ja HA and Myung-Ki CHEOUN. Contents. Motivation Formalism - Deformed basis (Nilsson basis) - Deformed Bardeen Cooper Schrieffer (DBCS)

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Gamow-Teller Transitions for Light Nuclei by the Deformed Quasi-particle RPA(DQRPA)

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  1. Gamow-Teller Transitions for Light Nuclei by the Deformed Quasi-particle RPA(DQRPA) Soongsil University, Korea Eun Ja HA and Myung-Ki CHEOUN 2011 HNP

  2. Contents • Motivation • Formalism - Deformed basis (Nilsson basis) - Deformed Bardeen Cooper Schrieffer (DBCS) - Deformed quasi-particle random phase approximation (DQRPA) - Gamow-Teller transitions for the nuclear beta decay • Results • Summary 2011 HNP

  3. Motivations Formalism Results Summary ～3hours Supernovae Type II X-ray and Super Burst Time scale　： ～ a few hours Total energy : 1042 erg (normal burst ~ 1039 erg) 2014-08-21 SKKU, 17 June. 2010 31 2011 HNP

  4. Motivations Formalism Results Summary Pycno‐reaction (Haensel & Zdunik1990 ) Because of high density and low temperature on the neutron star crust,Coulomb barrier is overcome by the zero-point motion of the nuclei in the solid lattice !! Degenerated electrons block the beta decay. Ordinary nuclei become highly unstable, and unstable nuclei become the normal stable nuclei at the neutron-star crusts !! 2014-08-21 SKKU, 17 June. 2010 41 4 2011 HNP

  5. Motivations Formalism Results Summary • The conventional approach so far to understand the nuclear structure is based on the spherical symmetry. spherical basis deformation np-pairing correlation Considering nuclear deformation and np-pairing correlations will modify the occupation probabilities. The Gamow-Teller transition as well as other transition also will be affected. 2011 HNP

  6. Motivations Formalism Results Summary We extend our previous QRPA based on the spherical symmetry, which turns out to be a very useful tool for relevant reactions in the nuclear-astrophysics. 2011 HNP

  7. Motivations Formalism Results Summary Formalism Deformed WS Deformed BCS Deformed QRPA Gamow-Teller transition Without np-pairing With np-pairing(in progress) Realistic two body interaction taken by Brueckner G-matrix based on the Bonn potential 2011 HNP

  8. Motivations Formalism Results Summary Axially symmetric harmonic oscillator w.f. • The single particle states Spin w.f 2011 HNP

  9. Motivations Formalism Results Summary Spherical harmonic oscillator w. f. • The deformed basis(Nilsson basis) is expanded By Including deformation 2011 HNP

  10. Motivations Formalism Results Summary Deformed BCSIn order to renormalize the G-matrix, theoretical values are adjusted to the empirical pairing potentials by multiplying the G-matrix with a strength parameters gpp(gnn). By Including deformation by a symmetric five term formula 2011 HNP

  11. Motivations Formalism Results Summary Description of Intermediate States for Gamow-Teller excitation K=1,0,-1 DQRPA equation 2011 HNP

  12. Motivations Formalism Results Summary Realistic two body interaction taken by Brueckner G-matrix based on the Bonn potential By Including deformation particle-particle particle-hole 2011 HNP

  13. Motivations Formalism Results Summary Beta- transition amplitude 2011 HNP

  14. Motivations Formalism Formalism Results Results Summary Summary Ikeda sum rule in percentage of 3(N-Z) 2011 HNP

  15. Motivations Formalism Formalism Results Results Summary Summary Experiment by Madey (1987) Gamow-Teller Strength in 26Mg 2011 HNP

  16. Motivations Formalism Formalism Results Results Summary Summary Ours 60Ni (p,n) 60Cu Experiment 60Ni (n,p) 60Co Gamow-Teller Strength in 60Ni 2011 HNP

  17. Motivations Formalism Formalism Results Results Summary Summary Gamow-Teller strength in 76Ge Calculatiion by Fedor. Experiment 2011 HNP

  18. Motivations Formalism Results Summary Summary 1. To describe a single particle state in deformed basis, we used the deformed axially symmetric Woods-Saxon potential. And then we performed the deformed BCS and deformed QRPA with realistic two-body interaction calculated by Brueckner G-matrix based on Bonn potential. 2. We calculated the Gamow-Teller transitions in 26Mg , 60Ni, and 76Ge. Our results are reproduced well the position of energy with available experimental data and other calculations but we have some problem for the B(GT) strength. 3. We are checking transition operator and np-pairing correlations to improve the B(GT) strength. 2011 HNP

  19. Future works 1. Next stage is E1 and E2 transitions in unstable nuclei to study the inversion island, which comes from the shell evolution sensitive to the deformation . 2. Weak interactions with unstable nuclei by the neutrino, in specific, stemmed from the supernova explosion are also one of the interesting topics, because relevant cross sections are believed to differ from those in stable nuclei and affect rapid processes in the nucleosynthesis on the corecollapsing supernovae and/or the crust of the neutron star with a binary star. 2011 HNP

  20. Thanks for your attention !! 2011 HNP

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